Pneumatic lifting mechanism

ABSTRACT

A pneumatic mechanism for lifting generally heavy appliances such as a washing machine from a stationarily supporting leg structure so as to be supported on casters to provide ready portability. The mechanism includes an air inflatable member disposed between a generally horizontal bottom wall of the appliance housing and a lower movable support plate having a plurality of attached casters. The support plate is mounted on the bottom wall for limited vertical movement as guided by rods and biased to a retracted position in close proximity to the bottom wall by springs to normally retain the plate and casters well above the floor in which the appliance rests. Inflation of the inflatable member causes the support plate to move downwardly, against the force of the springs, until the casters contact the floor. Further inflation lifts the appliance so as to be supported on the casters for easy manual portability. The guide rods, in addition, to guiding the vertical movement of the support plate, limit the amount of vertical movement and provide rigidity to the mechanism when in an inflated position. The inflatable member includes a valve which can be opened to release the air and deflate the member to once again lower the machine to its stationarily supporting leg structure.

United States Patent Millett Aug. 12, 1975 PNEUMATIC LIFTING MECHANISM[57] ABSTRACT lflventol'i Bl'ifdbllme Mme", Mansfield A pneumaticmechanism for lifting generally heavy Ohlo appliances such as a washingmachine from a station- [73 Assigneez white wesfinghouse Corporation,arily supporting leg structure so as to be supported on Cleveland Ohiocasters to provide ready portability. The mechanism I includes an airinflatable member disposed between a Flledi y 1974 generally horizontalbottom wall of the appliance [21] Appl No; 472,340 housing and a lowermovable support plate having a Related US. Application Data plurality ofattached casters. The support plate is mounted on the bottom wall forlimited vertical move- [63] Continuation of Ser. No. 303.580, Nov. 3,1972, ment as guided by rods and biased to a retracted posiabandoned.tion in close proximity to the bottom wall by springs to normally retainthe plate and casters well above the [52] US. Cl. 280/4324 floor inwhich the appliance rests. Inflation of the in- [51] Int. Cl. B62D 21/18flatable member causes the support plate to move [58] Field of Search280/4324, 43.13, 43.14, downwardly, against the force of the springs,until the 280/4323; 180/ 124 casters contact the floor. Furtherinflation lifts the appliance so as to be supported on the casters foreasy [56] References Cited manual portability. The guide rods, inaddition, to UNITED S S ENTS guiding the vertical movement of thesupport plate, 1,892,406 12/1932 Meyercord 280/43.14 f f the amount of Yand f 2 812 189 11/1957 Geldhof 280/4314 gldlty to the mechanism when anInflated P 3.179338 4/1965 Field 43 4 The inflatable member includes avalve which can be 3.261765 8/1966 Just 280/4324 Opened to release theair and deflate the member to 3,285,621 11/1966 Turner... 280/4323 onceagain lower the machine to its stationarily sup- 3,353,62l 1 l/l967ClCVCiI l80/l24 porting leg structure Primary ExaminerRobert R. Song 6Claims, 3 Drawing Figures E Q t. 2

: I 28 26 I I, i

PNEUMATIC LIFT ING MECHANISM This is a continuation of application Ser.No. 303,580 filed Nov. 3, 1972, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The inventionrelates to a mechanism for transferring the weight of a normallystationarily supported appliance to support structure providing easyportability of the appliance, and more particularly to a pneumaticmeans, disposed between a bottom wall of the appli ance housing and thesupporting surface such as a floor, which is inflatable to a sufficientdimension to lift the machine from resting on the leg structuredepending from the housing to casters associated with the mechanism.

2. DESCRIPTION OF THE PRIOR ART Various mechanisms for providingrelatively easy portability of heavy household appliances are well knownin the art. Such mechanisms however must also include some means ofpreventing unwanted movement of the appliance which can be induced fromthe vibration produced as the appliance operates. Therefore, to satisfythe requirements of portability yet provide a generally stationarysupport even under extreme operating conditions, such as an automaticwashing machine having an uneven load distribution during the spin drycycle, the structure provided generally either permanently supported theweight of the appliance on casters with a manually actuated brakingmechanism for the casters which maintained the appliance generallystationary, or, included a mechanism which would transfer the weight ofthe appliance from structure such as legs providing the stationarysupport to structure providing ready portability, which in mostinstances, included casters.

The first mentioned mechanism, although generally the least expensive,had a disadvantage in that the casters surface tended to becomeflattened from supporting the machine which in turn, over the life ofthe machine, substantially effected their ability to roll.

The second mentioned mechanisms, although alleviating this disadvantageof the first, were generally more expensive in that they required somelifting mechanism to transfer the weight, and in the highly competitiveatmosphere of the appliance marketplace were prohibitively expensive.US. Pat. Nos. 2,671,242, 3,610,364, and 3,635,491 are exemplary ofrather expensive weight transferring devices to provide applianceportability.

SUMMARY OF THE INVENTION This invention relates to a simple andrelatively inexpensive mechanism to transfer the support of an appliancefrom legs providing stationary support to casters to provide easy manualportability and includes an inflatable diaphragm or tube interposedbetween the bottom wall of an appliance housing and a normally retractedsupport plate attached to the bottom wall through guide rods whichpermit a limited vertical movement of the support plate. The surface ofthe support plate facing the floor supports a plurality of casters.Inflation of the diaphragm to a sufficient pressure initially forces thesupport plate from a retracted position to a position forcing thecasters against the floor. Further inflation will thus lift theappliance from the generally stationarily supporting legs so that theappliance is then supported on the casters for rolling portability.Continued inflation forces the plate to the maximum position limited bythe guide means at which point the diaphragm and the guide meanscooperate to provide required rigidity to the inflated supportstructure. Further, spring means are interposed between the bottom walland the support plate to generally oppose the movement caused byinflating the diaphragm so that upon deflating the diaphragm the plateis retracted to a position elevating the casters above the floor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational cross-sectionof the lifting mechanism of the present invention attached to a laundryappliance; 1

FIG. 2 is an enlarged view of a portion of FIG. 1; and

FIG. 3 is a bottom plan view of the lifting mechanism as attached to thelaundry appliance of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Lifting mechanisms such as thepresent invention are used in many appliances; however, the presentinvention is disclosed in a center post agitator washing machine 10,which, as shown in FIG. 1, includes a housing 12 generally enclosing theoperating mechanisms of the appliance which are well known in the art.The housing also includes a bottom wall 14, which, in this case, iscontoured so as to provide utility in the pivotal support of the washingmachines tubs and drive mechanism. However, it is acknowledged that thebottom wall 14 could generally be of any desired configuration fromplanar to a contoured configuration such as shown. The appliance isgenerally stationarily supported by adjustable leg bolts 16 and a matingnut 18 secured to the bottom wall 14 to provide variable lengths to thesupport legs so that they can be adjusted to maintain the machine in asubstantially level position. Locking means such as lock nuts 20 areprovided for tightening the bolts once their properly extended positionhas been determined. Also, the bottom-most portion of the boltsterminate in a headed portion 22, which, in most instances, is enclosedby a resilient cap member 24 for the face-to-face contact with thesupport surface such as a floor and serves the dual purposes ofproviding a friction contact between the appliance and the floor tominimize movement of the machine, and provide a soft surface to preventscratching the floor.

The lifting mechanism of the present invention is shown in FIG. 2 in itsnormally retracted position and includes a generally planar supportplate 26 depending from the'bottom wall 14 of the housing 12 byattaching means 28 which provide limited vertical movement of thesupport plate with respect to the bottom wall 14. The attaching meansinclude guide bolts or rods 30 securely attached to the plate generallyadjacent its peripheral edge as by inserting them through apertures inthe support plate and capturing the support plate between opposedlocking nuts 34, 36 and slidably received within aligned apertures (notshown) in the bottom wall 14 with the internal end having an enlargedheaded portion 32 to prevent the bolt from exiting the bottom wall.

A coil spring 38 is interposed between and respectively attached to, asby a tack weld, the bottom wall 14 and the support plate 26 and coiledabout the guide rod 32 to normally bias the support plate to theretracted position shown. The support pl 'lc further has secured to itsbottom face a plurality or caster means 40 of well known construction.An airtight inflatable diaphragm 42 is interposed between the bottomwall 14 and the support plate 26 and includes an air inlet hose 44terminating in a valve means 46.

As seen in FIG. 1 but as more particularly pointed out in FIG. 3, thesupport plate of the present invention has a central opening generallyto accommodate the central contour of the bottom wall 14 of the housing.Also for this reason, the inflatable diaphragm 42 of the preferredembodiment is generally donut-shaped and in many ways resembles theinner tube of the well-known pneumatic tire. Further, the valve means 46associated with the air inlet 44 to the inflatable diaphragm alsoresembles the valve means generally associated therewith.

Under normal conditions, the appliance is stationarily supported on afloor or other support surface by resting on the friction pads 24 of thelegs or foot bolts 22. However, with the present invention, upondesiring to move the appliance from one position to another, thediaphragm 42 is inflated by attaching to the valve means 46 any wellknown air pumping devices such as a hand pump or a small compressor suchas is normally associated with household paint spraying device (eitherof which device is more than adequate to easily inflate the diaphragm toa pressure of approximately 5 pounds per square inch which, it has beenfound, is generally sufficient to expand the diaphragm to its operablesupport position) and the diaphragm is thereby inflated causing it toforce the support plate and bottom wall member 14 to separate as opposedinitially only by the spring 38 until the caster members have contactedthe floor surface. Further, inflation of the diaphragm 42 causes furtherseparation of the bottom wall and the support plate which from thispoint lifts the appliance from the foot bolts so that the weight of theappliance is supported on the support plate and consequently the castermembers through the diaphragm 42. It is desirable to inflate thediaphragm to the extent that the headed portions 32 of the guide rod 28are seated against the bottom wall 14 to provide rigidity and alleviateany tilting which may result from the rather non-symmetricallydistributed weight of the appliance. It is to be noted that the amountof travel permitted by the guide bolts prior to it becoming seated onthe bottom wall member 14 is more than sufficient to permit the castermember 40 to come in contact with the floor when the adjustable supportlegs 16 have even been extended to their uppermost limit.

To facilitate moving the appliance once it is supported on the casters,a handle, not shown, can be provided on the appliance at a suitablelocation. Through this arrangement, the appliance can then be manuallypositioned in any desired location. Once it is in the desired position,the valve means can be opened to permit the diaphragm to deflate whichin turn lowers the appliance so as to be once again supported on itslegs and further deflation causes the support plate 26 to be retractedto its normally retracted position through the action of the coilsprings 38. The machine thus again becomes generally stationarilysupported upon its support legs 16.

It is apparent that through the lifting mechanism of the presentinvention, once the diaphragm 42 has been properly inflated, the machinecan be rolled or maneuvered to any other location without regard to acontinuous air flow to maintain its elevated position and further it ismanifestly apparent that the lifting mechanism of this invention doesnot require any complex lever or linkage arrangement to lift theappliance nor does it have any expensive valving or sealing requirementsnor does it contain any fluid which may soil its surroundings should thediaphragm become punctured.

What we claim is:

1. A mechanism for transferring the support of an appliance from agenerally stationary relationship on a surface to a generally easilymovable relationship on the surface; said appliance having a bottomstructural member generally adjacent said support surface, and meansattached to said structural member providing frictional contact withsaid support surface for normally stationarily supporting said articlewherein said transferring mechanism comprises:

a support plate interposed between said structural member and saidsupport surface, said plate defining a first surface facing saidstructural member and an opposite surface facing said support surface;

means for attaching said support plate to said structural member forguided relative movement of one with respect to the other said attachingmeans including means for positively limiting said move ment to apredetermined maximum amount;

a plurality of casters attached to said opposite surface of said plate;and,

inflatable means interposed between said structural member and saidfirst surface of said plate for resiliently urging one away from theother to said predetermined amount which is sufficient to cause thecasters to contact the support surface in an appliance weight bearingrelationship whereby,

the weight of the appliance is transferred from said frictional supportmembers to be supported on said casters for easy portability by saidcasters rolling on said support surface and said appliance is generallyrigidly maintained in said caster supported position by abuttment ofsaid movement limiting means.

2. Structure according to claim 1 wherein said mechanism also includesspring means attached to said plate and said structural member forresiliently urging relative vertical movement towards each other inopposition to said inflatable means.

3. Structure according to claim 2 wherein said inflatable meanscomprises an annular tube and includes valve means for connection to asource of pressurized fluid, said valve means when closed capable ofmaintaining said inflatable member in an inflated condition.

4. An appliance having a housing and support means associated with saidhousing for generally stationary support of said appliance on a supportsurface and a lifting mechanism for transferring the weight of saidappliance from said stationary support means to caster structureassociated with said lifting mechanism wherein said lifting mechanismcomprises:

a support plate disposed between said housing and said support surface;

means for attaching said support plate to said housing for guidedmovement of said support plate with respect to said housing saidattaching means including means for positively limiting said movement toa predetermined distance;

having a biasing force in opposition to the lifting force of saidinflatable member for normally retaining said plate and said housing ingenerally close proximity when said inflatable member is not inflated.

6. Structure according to claim 5 wherein said inflatable memberincludes valve means for connection to a source of pressurized fluid,said valve means being capable of maintaining said inflatable memberinflated when closed.

1. A mechanism for transferring the support of an appliance from agenerally stationary relationship on a surface to a generally easilymovable relationship on the surface; said appliance having a bottomstructural member generally adjacent said support surface, and meansattached to said structural member providing frictional contact withsaid support surface for normally stationarily supporting said articlewherein said transferring mechanism comprises: a support plateinterposed between said structural member and said support surface, saidplate defining a first surface facing said structural member and anopposite surface facing said support surface; means for attaching saidsupport plate to said structural member for guided relative movement ofone with respect to the other said attaching means including means forpositively limiting said movement to a predetermined maximum amount; aplurality of casters attached to said opposite surface of said plate;and, inflatable means interposed between said structural member and saidfirst surface of said plate for resiliently urging one away from theother to said predetermined amount which is sufficient to cause thecasters to contact the support surface in an appliance weight bearingrelationship whereby, the weight of the appliance is transferred fromsaid frictional support members to be supported on said casters for easyportability by said casters rolling on said support surface and saidappliance is generally rigidly maintained in said caster supportedposition by abuttment of said movement limiting means.
 2. Structureaccording to claim 1 wherein said mechanism also includes spring meansattached to said plate and said structural member for resiliently urgingrelative vertical movement towards each other in opposition to saidinflatable means.
 3. Structure according to claim 2 wherein saidinflatable means comprises an annular tube and includes valve means forconnection to a source of pressurized fluid, said valve means whenclosed capable of maintaining said inflatable member in an inflatedcondition.
 4. An appliance having a housing and support means associatedwith said housing for generally stationary support of said appliance ona support surface and a lifting mechanism for transferring the weight ofsaid appliance from said stationary support means to caster structureassociated with said lifting mechanism wherein said lifting mechanismcomprises: a support plate disposed between said housing and saidsupport surface; means for attaching said support plate to said housingfor guided movement of said support plate with respect to said housingsaid attaching means including means for positively limiting saidmovement to a predetermined distance; said caster structure attached tosaid support plate for rolling contact with said surface; and inflatablemeans positioned between said housing and said support plate forinflation to separate them said predetermined distance which is at leastsufficient to raise said stationary support structure attached to saidhousing from contact with said support surface and abutt said movementlimiting means.
 5. Structure according to claim 4 including spring meansconnected between said plate and said housing having a biasing force inopposition to the lifting force of said inflatable member for normallyretaining said plate and said housing in generally close proximity whensaid inflatable member is not inflated.
 6. Structure according to claim5 wherein said inflatable member includes valve means for connection toa sOurce of pressurized fluid, said valve means being capable ofmaintaining said inflatable member inflated when closed.